[Br:1]N1C(=O)CCC1=O.[CH3:9][C:10]1[CH:22]=[CH:21][C:13]([C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])=[CH:12][CH:11]=1.C(O)(C)(C)C.C(OOC(=O)C1C=CC=CC=1)(=O)C1C=CC=CC=1>C(Cl)(Cl)(Cl)Cl>[Br:1][CH2:9][C:10]1[CH:22]=[CH:21][C:13]([C:14]([O:16][C:17]([CH3:19])([CH3:18])[CH3:20])=[O:15])=[CH:12][CH:11]=1
N-Bromosuccinimide (NBS) (35.8 g, 0.20 mol) was added in several portions to a solution of 1,1-dimethylethyl 4-methylbenzoate (prepared by the reaction of the respective acid chloride with t-butanol.) (38.0 g, 0.20 mol) and benzoyl peroxide (0.36 g, 1.5 mmol) in carbon tetrachloride (1200 mL) at vigorous reflux. Another portion of benzoyl peroxide (0.36 g, 1.5 mmol) was added just before the final addition of NBS. After the foaming subsided, the reaction mixture was cooled to room temperature, washed with water (2×60 mL) and dried over magnesium sulfate. Filtration and concentration provided an oil that was purified by HPLC on silica gel eluting with a mixture of hexanes and ethyl acetate to give 1,1-dimethylethyl 4-bromomethylbenzoate (21.4 g) in 40% yield.
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